Fine particle matter (PM2.5) is recognized as atrial fibrillation (AF) risk factor, especially for older adults. However, studies on the relationship between PM2.5 and AF were inconsistent. Herein, we present a systematic review to further assess the correlation between PM2.5 and AF in older adults (average age > 50 years old). A comprehensive search was conducted with the keywords in PubMed (675 records), Web of Science (1130 records), Embase (82 records), and the Cochrane Library (42 records). Using Stata12.0 software to test the heterogeneity between studies, and select the corresponding model to calculate the comprehensive effect value, odds ratio (OR, odds ratio), the pooled %-change (percentage change) and its 95% confidence interval (CL, confidence interval). A total of 16 observational studies were included, involving 10,580,394 participants, the results showed that PM2.5 had an adverse effects on AF in older adults. An association was found between exposure to PM2.5 (per 10 μg/m3 increase) and AF in older adults, with the corresponding pooled OR (1.11, 95% CI: 1.03–1.19) and pooled %-change (1.01%, 95% CI: 0.14%–1.88%). Our study indicated that PM2.5 exposure was significantly related to increased incidence of AF in older adults. Both the pooled OR and %-change value were higher in areas with higher levels of PM2.5(≥25 μg/m3).